Molding



M arch l0, 1931*. R. .JONKERGOUW ET AL 1,796,203

MOLDING F'iled NOV. 22, 1928 Patented Mar. 1o, 1931 UNITED STATES PATENT oFFlcE BENIEL JONKERGOUW, F BRY O TH MIARNEAN D JACQUES DEMONGEOT,.0F

LYON, FRANCE HOLDING Application led November 22, i928, Serial No. 321,261, and in France November 30, 1927.

In molding under pressure certain plastic, pasty or other materials practice has shown that, up to a certain height from the bottom of the mold, the periphery of the work to be 6 molded does not receive normally pressure 'from the counter-mold. As a result, the particles ofall that portion of the material, not being subjected to the molding-pressure, fail tov agglomerate properly together, do not take 1.0 the details of the mold and do not form one body With the' remainder of the material, which remainder is perfectly agglomerated.

' The object of this invention is to bring to the molding methods hitherto in use an iml provement calculated to do away with the above set forth deficiency and topensure the obtaining of perfectly molded work.

As diagrammatically shown by the only figure in the drawingappended hereto, said improvement consists in providing on the Whole of the upper periphery of the material Scontained in mold 1 a groove or recess 4 and in filling the latter with sand 5 or with any other inert substance, preferably' pulverulent, of such a nature as not to be modified under the action of the temperature at which pressure is eiiectuated. Molding is then conductedin the ordinary manner by means of the countermold 2. l The packing with sand 5 or with other suitable material so arranged in the groove or recess 4 has the eiect of distributing the pressure over thewhole of the periphery of the mass therebyV permitting of obtaining molded Work absolutelyconformable to the minutest details of the mold and the edges of which offer cleanest sharpness.

Having now particularly ascertained and described the nature of our sai inventionas well as the maner in which the ame is to beI l performed -,.-we declare that what weclaim is:

1. In the\-'method of molding plastic materiaL'the steps which consist in providing on the upper periphery of the material with pulverulent material, and applying pressure to the contents of the mold. Y

2. In the method of molding plastic material, the steps which consist inproviding a groove along the upper periphery of the mahoused in the mold a recess, illing said recess` terial 'in the mold, packing sand in said groove, and applying pressure to the contents of the mold.

.In testimony whereof, we aix our signa-A 

